Apparatus for washing air, gases, or vapors



July 10, 1945. A. NEWCOMB APPARATUS FOR WASHING AIR, GASES, 0R VAPORSFiled Dec. 5, 1942 INVENTOR.

Patented July 10, 1945 APPARATUS FOR WASHING AIR, GASES, OR VAPORS AvonLockhart Newcomb, Birmingham, Mich, as-

signor to Ncwcomb-Detroit Company, Detroit,

Mich.

Application December 5, 1942, Serial No. 467,944

6 Claims.

This invention relates to means for the safe and effective removal ofparticles, such as explosive dusts which are produced in the grinding ofor otherwise shaping magnesium alloys, or dusts of other combustiblesubstances, or inert dusts such as sand, dirt and other solids, ordroplets such as paint, oil, and other liquids, from air or other gasesor vapors. For simplicity this application hereinafter describes andillustrates apparatus for washing dust out of air by means of water; itbeing understood that other suspended. substances, can be similarlyremoved from gases or vapors by washing with liquids other than water.

More particularly this invention relates to the means used for mixing astream of air, carrying dust in suspension, with water picked up in adense spray by the moving air, whereby the air and water are sothoroughly intermingled that practically all the dust is eliminated andthe air leaves the washing compartment in a purifled condition.

One object of my invention is to raise water in an approximately conicalheap immediately below an orifice by means of reduced air pressure in asuperimposed chamber or space whereby the suction and the resulting airflow converging upwardly into the orifice will keep the heap of water ina violently agitated condition and scour spray from its surface.

Another object of my invention is to cause dust laden air commingledwith a dense spray of water to impinge against a surface, such as asheet of metal, and thereby press the dust and water together in orderto ensure that the dust particles are thoroughly wetted.

A further object of my invention is to cause the water rebounding fromthe surface against which it is impinged to be deflected in a directiontransverse to air flow, in such manner that Wetted dust particles arepropelled by the rap idly moving deflected water against a suitablylocated surface along which the water descends to a tank collector.

The advantages of this apparatus will beapparent from the followingdescription of an embodiment of my invention and the novel features areclearly set forth in the appended claims. I

In the accompanying drawing the figure is a sectional elevation of. adevice constructedin accordance with the invention. V

Referring to the drawing and to the desig nating numerals thereon, Iindicates'a casing which may be of any suitable shape but for example isillustrated as cylindrical. The lower end of the casing is closed, as bythe base sheet 2, so as to form a water reservoir 3 which is also usedas a sludge tank for the collection of materials washed out of air.These materials settle to the bottom of the reservoir and can be removedas and when required through a suitable clean out passage as at t havingsides projecting from and welded to the casing l and provided withclosing lneans such as the hinged lid 5.

Water is supplied to the reservoir 3 from any suitable source, such as aservice pipe connected to .the side of the reservoir to deliver waterthrough the opening 6, which can be fitted with a float Valve, notshown, to maintain a suitable levelin an ordinary well known manner.Water can leave the reservoir 3 through an overflow opening i, or can bedrained through the opening 8 near the base sheet 2.

A source of power such as an electric motor 9 is mounted at the top ofthe casing l. The top of the casing l is closed, as by a sheet of metalIt, below which a parallel sheet of metal ll is provided at a suitablevertical distance.

Between the metal sheets 10 and II an involute fan housing is formed bythe scroll sheet I I2, within which a fan impeller I3 is placed andsecured by a hub l4 keyed to the shaft 15 of the motor 9. An inlet it isprovided to admit air'to the impeller l3 and an outlet I1 is providedfor the discharge of air. The arrangement of the motor drivencentrifugal fan shown is merely illustrative, as other arrangements canbe used such for example as a centrifugal fan with a horizontal axis oralternatively an," axial flow fan. Also it is not essential that the fanshould operate as an exhauster as shown, as a blower type of fan couldbe employed located elsewhere than as shown and delivering air to mydevice instead of withdrawing air from it. A fan operating as anexhauster is preferable for this service, because it receives clean airand is, therefore, not subjected to the abrasive effect of dustparticles moving at high velocities.

At a suitable distance below the metal sheet ll another sheet of metalforming a shelf i8 is placed, supported as by an angle iron ringiilfastened to the casing i. This shelf is provided with an opening 20having an adequate area for the volume of air to be dealt with by mydevice.

On the shelf I8 a suitable liquid eliminator 2| may be placed and may bewithdrawable through the opening 22 covered by the door 23. Below theshelf I8 is a mist chamber 24, access to which may be had by an opening25 covered by the door 26.

At the bottom of the mist chamber 24 is a boundary sheet of metal whichmay be in the form of a truncated cone 2] terminating in an convergeswithin the annular ring 28 and rushes upwards into the mist chamber 24,it raises the water in the reservoir 3 into an irregular heap in anagitated condition as shown in Figure 1 and spray is copiously picked upby the air from the wavelets on the surface of the Water.

The upwardly moving air carrying the dust still in suspension and waterspray strikes a surface such as the sheet metal disc 30, the impactcompressing the dust and water particles together, whereby the dustparticles are thoroughly scrubbed with water and wetted.

The mixture of air, light dust, and water spray moves radially outwardin all directions along cone 2'! passes through the center of the disc30,

thereby causing the disc 30 to be concentrically positioned within thetruncated cone 21.

Below the truncated cone 21 and above the surface of the water in thereservoir 3 is a space 32 circumferentially bounded by the casing Icontaining dust laden air which enters through an inlet opening 33 intoa side passage 34, the walls of which are welded, or otherwise joined,to the casing The arrangement of the inlet 33 shows a method ofintroducing air which is to be purified, adapted to the use of anextraneous duct system collecting dust laden air from various sources,as the terminal duct of such a system can be suitably joined to a flangearound the inlet 33. Other methods of admitting air to my device can beused, as for example a large opening can be provided in the side passage34 through which air to be purified can enter from an adjoining spacesuch as a paint spray booth, without the use of any ducts.

The operation of my device is as follows:

The reservoir 3 is filled to a desired level with water, after which thefloat valve, not shown,

- fitted to the supply opening 6 will maintain the water level for whichit is adjusted. Adjustment can be such that the float valve will not befully closed when the surface of the water is at the level of the lowestportion of the circumference of the overflow opening 1 and this willpermit water to be constantly supplied to the reservoir 3 in sufficientquantity to prevent undue concentration of solids in suspension in thewater within the reservoir and to replace the water lost by evaporation.

Auxiliary appliances such as solenoid valves, not shown, can if desiredbe provided in the extraneous water supply and overflow lines, in serieswith thefan motor 9, so that water will only flow when the motor isoperating.

The motor 9 is started and the fan impeller I3 is rotated at a suitablespeed. Air is withdrawn from the space within the casing therebycreating a partial rarefaction which causes air to flow into my devicethrough the inlet 33 to the space 32.

Due to the downward direction of the entering air the relatively largeand heavy dust particles carried in suspension plunge into the water inthe reservoir 3 and gravitate to the base 2.

The air then flows from the space 32 above the mean level of the watertherein converging through an orifice such as the annular ring 28 intothe hollow within the truncatedcone 21, carrying with it the lighterdust still in suspension.

As the air stream at suitably high velocity cated cone 21.

the lower surface of the disc 30 and the water carrying the wetted dustis deflected by the bevelled rim 3| and is thereby caused to impinge ata high velocity and at an angle of approximately degrees against theupper surface of the truncated cone 21.

The impact of impingement against the truncated cone 21 again compressesthe dust and water particles together and most of. the water, carryingwith it most of the dust fiows down the upper surface of the truncatedcone 2! and falls into the reservoir 3 where the dust settles to thebase 2. I

The water descends in a circular curtain from the annular ring 23 whichterminates the truncated cone 21 and in falling through the stream ofair which is entering the annular ring some'of the water is whirledupward and again strikes the lower surface of the disc 30.

This upward re-entry of water within the annular ring 28, its separationinto drops due to the swiftly moving air, and the collision of thesedrops with the water spray picked from the surface of the heap of wateras previously described produces fine atomization. The air and waterspray swirl in a very turbulent'condition in the space below the disc30.

The air in passing from the space below the disc 30 to ascend into themist chamber 24 is compelled to pass transversely through the waterwhich is projected from the rim 3| to the trun- The area of the gapbetween the rim 3| and thetruncated cone 2'! is of prime importance andit is determined on the basis of providing not less than the requiredcritical air velocity at this point. It has been found that this airvelocity should not be less than 1200 feet per minute through the fullarea of said gap, without any allowance for the reduction in eifectivearea caused by the water which is projected across said gap uniformlywhen ,thefan is in operation. If the air velocity is too 1ow,fwater willnot be uniformly projected across the gap at all points and dust ladenair will pass through any portions of the gap devoid of water, withoutbeing subjected to cleansing.

The mist chamber 24' contains water particles carried into it by theascending air which constitute nuclei for the adhesion of any remainingfinely divided float dust which due to its very low inertia may havechanged direction of movement almost as quickly as airand escapedimpingement successively against the surface of the water in thereservoir 3, against the lower surfaces of the disc 30 and against theupper surface of the truncated cone 21.

The air passes from the mist chamber 24 through the eliminator 2| whereentrained water is removed and thence to the fan impeller 3 from whichit is discharged in a purified condi tion through the outlet I I. r

The invention has been described in connection with an embodiment whichhas been found useful in removing dust from air, and with an alterationof the air inlet as herein mentioned in removing atomized paint fromair. It will be obvious that devices constructed in accordance with thisinvention can also be used for cleaning various gases or vapors by meansof various liquids. It will also be understood that while I have hereindescribed and illustrated one embodiment of my invention, variations indesign and construction can be made without departing fromthe spirit andessence of the invention. For instance, the casing can be rectangular inhorizontal cross sectioninstead of circular as shown; the interiorpartition 21 can be in the form of a truncated pyramid or alternativelya truncated cone; and other means can be used for removing entrainedwater from the leaving air instead of the eliminator 2!. Also a numberof truncated cone-s or pyramids instead of only one can be placed withina casing and used with one or more fans in a single apparatus or unit.Furthermore one or more units can be connected to one or moreextraneously placed fans which can be either of the exhauster or blowertype.

Having described my invention, what I claim and desire to secure byLetters Patent of the United States is:

1. An apparatus for washing air comprising a casing through which air iscaused to flow, having a lower portion forming a reservoir with a bodyof water therein, and within said casing a hollow truncated coneterminating at its lower end in a neck bounding an orifice which ispsitioned above and adjacent to the surface of the water in saidreservoir, a horizontal flat circular plate with a downwardly inclinedbevelled rim concentrically positioned within said truncated cone andabove said orifice, the said bevelled rim presenting a surfacesubstantially normal to the interior surface of said truncated cone, aneliminator positioned above said flat circular plate and means forcausing flow of air at suitably high velocity through said casingwhereby spray is copiously picked up by said air from the surface of thewater in said reservoir and is caused to successively pass through saidorifice, impinge against said flat circular plate and thence beprojected in a dense sheet against the inner surface of said truncatedcone.

2. An apparatus for washing air comprising a shell with its lowerportion adapted to contain a liquid, partition means within said shellin the form of a truncated cone with an orifice at its lower end, saidorifice being above the surface of a body of liquid in the lower portionof said shell and adjacent thereto, a horizontal disc deflector with adownwardly flaring rim substantially perpendicular to the inner surfaceof said truncated cone, an eliminator placed beyond said disc deflectorin the direction of air flow, and fan means for causing air to entersaid apparatus stituting a reservoir containing a body of water, funnelshaped partition means separating the lower portion of said casing fromits upper portion, said partition means terminating at its lower end inan orifice positioned above the mean level of the surface of said waterand adjacent thereto, a disc deflector with a downwardly inclinedperiphery positioned above said orifice and within said casing in suchmanner that an annular gap is provided between the circumference of saiddisc deflector and the inner surface of said funnel shaped partitionmeans for upward air flow, and an eliminator placed beyond said discdeflector in the direction of air flow, whereby air is caused to swiftlyflow sequentially above the surface of said body of water, then upthrough said orifice taking with it spray copiously'picked from thesurface of said water immediately below said orifice, the mixture of airand spray then impinging against the underside of said disc deflector,the air then flowing upwardly through said annular gap which surroundssaid disc deflector and passing transversely through densely compactedspray which is projected from the periphery of said disc deflectoracross said annular gap, the air subsequently flowing through saideliminator.

4. In an air cleaning apparatus comprising an enclosing casing throughwhich an air stream is caused to flow by a fan, a reservoir containing aliquid, boundary means above the surface of said liquid containing anorifice which gives access to an upper compartment within said casing,said boundary means increasing in cross sectional area in the directionof air flow, and a deflector having substantially the form of aninverted circular dish with its downwardly sloping peripheral portioninclined at an angle of approximately degrees to a horizontal plane,said deflector being and to flow over the surface of said liquid andWithin said upper compartment, and said deflector being of such size asto provide a gap for air flow between its perimeter and the interiorsurface of said upper compartment of such predetermined cross sectionalarea in relation to the volumetric capacity of said air stream as toproduce not less than the required critical air velocity through saidgap, whereby said air stream enters said casing and flows above thesurface of said liquid and converges at suitably high velocity into saidorifice to agitate thereunder the surface of said liquid and tocopiously pick spray therefrom, said spray being impinged against theunderside of said deflector and flowing outwardly from its perimeter ina dense stream across said gap to the inside surface of said uppercompartment, and said air stream flowing through said gap in a directiontransverse to the direction of fiow of said dense spray stream.

5. In apparatus of the class described a casing divided by partitionmeans into a lower and an upper portion, the said lower portion beingadapted to contain a liquid which has a predetermined surface levelmaintained by a controlled liquid supply and a fixed run off level foroutflow, the said partition means being conical in forma tion andterminating at its lower end in a ring enclosing an orifice, saidorifice being above and adjacent to the surface of said liquid, adeflector having the shape of an inverted circular dish with adownwardly flaring rim situated above said orifice in such manner as toprovide an annular gap for air flow at or above the required criticalvelocity between the rim of said deflector and the inner surface of saidpartition means, an elimideflector and thence be projected in a densesheet or curtain across said annular gap, whereby said air stream inflowing through said gap is caused to flow at an obtuse angle to thedirection of flow of said spray curtain and to thereby cause forcefulcollision of said air and spray streams.

6. An air washing apparatus comprising in combination a container havinga liquid reservoir I therein, said container having air entrance andexit openings and having an upper interior portion in the form of atruncated cone terminating at its lower end in an orifice positionedabove the surface of a body of liquid placed in the lower portion ofsaid container, disc deflector means with a downwardly inclined bevelledrim positioned above said orifice and concentrically within said upperinterior portion of said container, eliminator means positioned abovesaid disc deflector, and means for causing air to flow through saidapparatus whereby spray is picked up from the surface of said liquidsolely and entirely by said air flow and is caused to wash the air whichpasses through said apparatus.

AVON LOCKHART NEWCOMB.

